The inventive concept relates to solar cells and methods of manufacturing an electrolyte and, more particularly, to dye-sensitized solar cells and methods of manufacturing an electrolyte in the dye-sensitized solar cells.
Dye-sensitized solar cells may cause various problems such as leakage of an electrolyte solution, desorption of a dye caused by the electrolyte, precipitation of the electrolyte at a low temperature, and corrosion of an electrode. Thus, a new electrolyte may be urgently demanded. Unlike p-n junction solar cells, electrons excited from the dye of the dye-sensitized solar cells may be transmitted to a porous oxide thin layer and then electrons of a hole-transfer material are transmitted to the oxidized dye, such that the oxidized dye is deoxidized.
When I−/I3− currently used as an oxidation-reduction reactive agent is used, efficiency of 11% may be obtained. However, the reduction of the dye may require energy of about 0.6 eV. It corresponds to energy loss in operation of the solar cell. Thus, it is required to develop a new oxidation-reduction agent capable of being replaced with I−/I3−.
Thus, various researches have been conducted for solidification of the electrolyte of the dye-sensitized solar cells. A p-type inorganic semiconductor, a hole-transfer material, and a gel electrolyte using a polymer have been used in the dye-sensitized solar cells. However, these may not permeates into a nano-porous TiO2 electrode very well, such that efficiency may be lowered. Additionally, when a polymer electrolyte is used, diffusion length of carriers may be limited due to low conductivity of the polymer electrolyte. Moreover, when an electrolyte including nano-particles is used, even though a leakage problem may be partially resolved, it includes a solvent (e.g., 4-tert-butylpyridine, iodine) having high volatility. Thus, various problems may occur.